Aggie Ingeniero, September 2007

NMSU expert to inspect Minneapolis bridge disaster site

A New Mexico State University civil engineering professor has been invited to perform a preliminary inspection of the Minneapolis bridge that crashed into the Mississippi River Wednesday, Aug. 1, killing at least five people. NMSU has conducted the nation’s only Bridge Inspection Training Program for more than 35 years.

Ken White, academic department head of civil engineering at NMSU, was contacted by the National Transportation Safety Board to get a first-hand look at the disaster site and other information related to the Interstate 35W bridge.

“I hope to get a better feel of the sequence of events that led to the bridge failure,” White said. “I may be able to provide some thoughts and ideas as to what was happening.”

White was contacted via email to examine the bridge by inspectors from the NTSB who had attended one of NMSU’s Bridge Safety Inspection Programs.

“Professor White is a national leader in bridge inspection,” said Steven P. Castillo, dean of NMSU’s College of Engineering.

Most bridge inspection techniques rely on visual observation and measurements of physical properties. White said that assessing internal problems is difficult. NMSU researchers have developed “smart bridge” technology that monitors bridge performance from the inside, and may help to prevent bridge disasters and save lives in the future.

“Smart bridge” technology incorporates the use of fiber optic sensors that monitor how bridges perform under day-to-day stresses from use and weather. Three of the bridges already have been installed in New Mexico and may some day be the standard in bridge construction.

“Instead of relying on visual inspections of the bridge, the sensors will tell us on a continual basis how much the bridge is stressed and how it is performing under load,” civil engineering professor Rola Idriss said.

The fiber-optic sensors, built into the concrete girders during the fabrication process, send beams of light through the structures, measuring changes in temperature and shape that indicate stress within the bridge. Data is collected from computer equipment in a protective cabinet at the bridge site.

The technology is not only improving bridge safety, Idriss said, but also “allowing us to get more information on the new materials that are being used in bridge construction.”

Castillo said NMSU “will continue to work with state and federal authorities to help ensure that our bridges are safe for the public.”